Justification:
This small endemic electric ray has a very limited known distribution in the waters of the outer shelf in depths of less than 300 m off southwestern Taiwan, Province of China. The Taiwanese Blind Electric Ray (Benthobatis yangi) is taken as bycatch in the local shrimp trawl fishery, which uses nets of very fine mesh, likely preventing any capture avoidance. The level of bycatch is not known, however the species is generally retained by the fishing vessels and discarded on landing. The species may also be discarded at sea. Although little information has been gathered on its biology and ecology, the high level of endemicity suggests that this species is threatened by incidental fishing mortality. Given that intense shrimp trawl fisheries operate throughout this species’ limited range, it is assessed as Vulnerable on the basis of suspected declines as a result of continuing, high levels of exploitation.

Apparently occurs on the upper continental slope or outer shelf at depths of 300 m or less (Carvalho et al. 2003). Male Benthobatis yangi are sexually mature between 19.1 and 21.5 cm total length (TL). The smallest male paratype (16.1 cm TL) possessed undeveloped claspers which did not project beyond the pelvic fins. The largest male specimen (21.5 cm TL) possessed fully developed claspers with calcified terminal cartilage components. The 19.1 cm TL male possessed claspers that projected well beyond the pelvic fin posterior margins, but was without fully calcified terminal cartilages and appeared to be an intermediate between the smallest and largest males. A large female (25.7 cm TL) was assumed to be sexually mature due to its relatively large size (Carvalho et al. 2003).

The primary threat to the Taiwanese Blind Electric Ray is shrimp trawling throughout its limited distribution, where it is taken as bycatch. Shrimp trawl fisheries operate along the southwestern coast of Taiwan Island and may range down to depths of 500 m (D. Ebert pers. obs. 2007). Fine mesh nets are used in this fishery, thus it is unlikely that the species can avoid or escape the nets, which may also be causing habitat damage.

Carvalho, M.R. de. 1999. A systematic revision of the electric ray genus Narcine Henle, 1834 (Chondrichthyes: Torpediniformes: Narcinidae), and the higher-level phylogenetic relationships of the orders of elasmobranch fishes (Chondrichthyes). Unpublished Ph.D. thesis. The City University of New York.